Okay, so I have a quadcopter/drone whose model is LH-X4. The problem is that my Li-Po battery just died and I have also taken out the drone also after a long time and now I have moded it run on a power bank. But when i start to give throttle a point comes when the drone just powers off without even lifting. I have tried raising it very slowly but everytime it just powers off automatically when I raise the throttle to that certain point. I don't know wheter this is an issue of the drone or the Power bank please help me fix this problem.